In the Wednesday, June 17 issue of Us Weekly, Stephanie Pratt opens up about her body image issues and her secret battle with bulimia. She says that the disease was brought on by the pressure to stay stick-think, while filming The Hills. Keep reading for more details…

According to the Us Weekly report,the 23-year-old reveals she began bingeing and purging after watching a scene she shot with Lauren Conrad in 2007 after first joining the cast: “I was horrified. I remember saying, ‘I can’t believe how huge I look walking over to Lauren.’”

Another time, when filming in Hawaii in bikinis, the size 0-2 Pratt — in a bikini and cover-up — asked costar Audrina Patridge, “What looks better, ‘shirt on or off?’” Patridge said ‘On.’” Says Pratt, “The producers never put pressure on us to lose weight,” but adds, “It’s embarrassing working with skinny girls.”

“The producers never put pressure on us to lose weight… [but] it’s embarrassing working with skinny girls,” Pratt told Us.